// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "paddle/phi/kernels/prelu_kernel.h"

#include "paddle/phi/backends/xpu/enforce_xpu.h"
#include "paddle/phi/core/kernel_registry.h"

namespace phi {
template <typename T, typename Context>
void PReluKernel(const Context& dev_ctx,
                 const DenseTensor& x,
                 const DenseTensor& alpha,
                 const std::string& data_format,
                 const std::string& mode,
                 DenseTensor* out) {
  using XPUType = typename XPUTypeTrait<T>::Type;

  const T* x_ptr = x.data<T>();
  const T* alpha_ptr = alpha.data<T>();

  T* y_ptr = dev_ctx.template Alloc<T>(out);
  if (out && out->numel() == 0) {
    return;
  }

  auto x_dim = x.dims();
  auto x_rank = x_dim.size();
  std::vector<int64_t> x_shape(x_rank);
  if (x_rank == 0) {
    x_shape = std::vector<int64_t>({1});
  } else {
    x_shape = common::vectorize<int64_t>(x_dim);
  }

  // mode = 0: channel_nchw, xshape = {n, c, h, w}, alpha_shape = {c}
  // mode = 1, channel_nhwc, xshape = {n, h, w, c}, alpha_shape = {c}
  // mode = 2, elementwise, deprecated in Paddle 2.x
  // mode = 3, alpha_shape = {} or {1}

  int xpu_mode = 0;

  if (mode == "channel") {
    if (data_format == "NCHW") {
      xpu_mode = 0;
      if (x_rank == 2) {  // special case for NC shape, use channel last mode
        xpu_mode = 1;
      }
    } else {  // NHWC, channel last
      xpu_mode = 1;
    }
  } else if (mode == "element") {
    xpu_mode = 2;
  } else if (mode == "all") {
    xpu_mode = 3;
  } else {
    PADDLE_THROW(common::errors::InvalidArgument(
        "Expected mode of prelu kernel is 'channel' or 'all', But got "
        "unsupported mode: %s.",
        mode));
  }

  int r = xpu::prelu(dev_ctx.x_context(),
                     reinterpret_cast<const XPUType*>(x_ptr),
                     reinterpret_cast<const XPUType*>(alpha_ptr),
                     reinterpret_cast<XPUType*>(y_ptr),
                     x_shape,
                     xpu_mode);

  PADDLE_ENFORCE_XDNN_SUCCESS(r, "prelu");
}
}  // namespace phi

PD_REGISTER_KERNEL(
    prelu, XPU, ALL_LAYOUT, phi::PReluKernel, float, phi::float16) {}
